Combustion engine



April 30,1946; PRIETO 2,399,507

' COMBUSTION ENGINE Filed Feb. 26, 1945 IN V EN TOR.

Patented Apr. 30, 1946 UNITED! STATES PATENT OFFICE Application February 26, 1945, Serial No. 579,705

3 Claims.

The invention relates to improvements incombustion engine, having two opposite pistons in every cylinder which will be closed at two ends, and the objects. of the improvements are: first, to obtain more power output from the engine with a given amount of fuel; second, to save weight and cost in the manufacture of the engine: third, in some of its forms, to prevent loss of fresh fuel; fourth, to get the burnt gases definitively expelled; and fifth, to cool with fresh air alternatively a part of the cylinders.

Other objects of my invention will be apparen from the disclosures in the accompanying drawing and following specification.

Some forms of the invention are shown in the accompanying diagrammatical drawing.

Fig. 1 is a plan sectional view of a unit in an internal combustion engine of the two-stroke cycle type emboding the invention.

Fig. 2 is a similar view in lesser detail, of an alternate form of the invention.

Fig. 3 is a plan sectional view of a single cylinder of an internal combustion engine of the radial two-stroke cycle type.

Referring to the drawing in greater detail and with more particular reference to Fig. l, the engine comprises, generally, parallel and closed ended cylinders 5 and 6, the cylinder 5 being provided with working pistons 1 and 8 and with a free piston 9 therebetween, and the cylinder 6 being similarly provided with working pistons HI and II and a free piston I 2. The engine further comprises a crankshaft l3; means operatively connecting the crankshaft and the working pistons 1 and I comprising connecting rods l4 and I5; similar means operatively connecting the crankshaft and the working piston 8 and II comprising connecting rods I6 and I1; an inwardopening valve l8 in each of the working pistons I, 8, III and H for allowing the fuel charge to pass through said pistons during the out-stroke when the pressureof said fuel charge is greater than various means and connections completing the engine structure.

The arrangement of the engine is such that the pistons I and III are directly connected to the connecting rods II and H by piston rods 22 and 23 respectively. However, the pistons 8 and H are connected to the connecting rods l6 and H by respective piston rods 24 and 25 which are each formcd'with a return bend to comprise U-shaped members, as shown. By means of this arrangement, a single crankshaft serves to receive the thrust of the four pistons I, 8, l0 and II.

Each valve [8 is placed in a hole or passage 26 in each piston I, 8, Ill and II. Said passage extending through each piston from face to face thereof.

The four fuel lines [9 and the four valves 20 are so arranged relatively and respectively as to control the admission to the cylinders 5 and G of air or fuel as the case may be. The relationship of the valves 20 to the fuel lines l9 may vary physically and the instrumentalities may vary in design and arrangement with the end in view, however, that the relationship permit the admission of air or fuel selectively and alternately.

' The structure of Fig. 2 is similar to that of Fig. 1 with the exception that the connections between the crankshaft l3 and the working pistons t and H have been modified. The modification entails an inertia member 30 interposed between said crankshaft and each working pistons t and H, as shown, said inertia member being able to deliver power.

The valves 20 and 2 I, in the usual manner, may be moved by a camshaft operatively connected to the crankshaft, or may be driven by an outside mechanism timed in proper synchronization with the operation of the engine.

The operation of the engine is as follows:

During the in-stroke of piston I, air was drawn into the cylinder 5, and during the in-stroke of piston ii, a fuel charge was drawn into said cylinder. Said pistons having finished their in-stroke, a combustion chamber is formed between piston I and the free piston 9. At that moment the fuel in the chamber C is ignited by suitable spark plugs, or other firing means not shown). The resulting gas expansion causes the out-stroke to begin, the pistons I and 8 moving outwardly and oppositely with the same velocity. The piston I receives its moving force directly from the expanding gases, and piston 8 is moved by the free piston 9 which similarly is impelled by the exploding and expanding fuel charge. During the following out-stroke, the position of the inlet and exhaust valves remain unchanged. Consequently piston l expells through valve 2B the air previously entered through the same valve. during the in-stroke, thus cooling the cylinder. and piston 8. while compressing the fuel charge previously entered through the valve 20, closes the back pressure valve 20a in the fuel line l9. and allows said fuel charge to pass through its valve is into the space between itself and the free piston 8. It follows then that the free piston 9. instead of following the out-stroke movement of piston 8. gradually slows up and reverses its movement toward piston I. impelled by the incoming fuel charge through piston 8. At the end of this out-stroke, the inlet and exhaust valves change their position. Now the pistons I and 8 begin their in-stroke during which the free piston 9 finally comes in contact with piston I thus the burnt gases being totally expelled through the exhaust valve 2| and the fuel charge between piston 8 and the free piston 9 being compressed to form a combustion chamber therebetween. Upon ignition of the fuel charge, the operation above is repeated except that, this time. during the in-stroke of piston l a fuel charge will be drawn into the cylinder, and during the in-stroke of piston 8 air will be drawn into said cylinder. The exhaust valves ii are operated in timed relation to the operation of the engine. One of the exhaust valves 2| is closed when the incoming fuel charge is compressed and exploded, and the other is opened when the burned gases are expelled. The valves are thus alternately operated as canbe well understood.

The engine is arranged so that the operation in cylinder is opposite to that in cylinder 6 to effect a balancing of the forces in the engine. Therefore, the pistons in the two cylinders move oppositely with respect to each other.

Only the essentials of the engine of my invention have been disclosed, and it is obvious that skilled persons can readily incorporate such other attending instrumentalities as may be needed to complete the structure. Further, many changes in the construction as disclosed may be made without departing from the spirit and scope of the invention as claimed. I, therefore, desire to reserve to myself such modification that may fall within the scope of the appended claims.

I claim:

1. An internal combustion engine comprising a crankshaft, parallel cylinders associated with the crankshaft, a pair of opposed working pistons in each cylinder. a freely movable piston between each pair of working pistons to form a combustion chamber between itself and its related working pistons alternately, means directly connecting one working piston of each pair to the crankshaft, and means comprising U-shaped members connecting the other working piston of each pair to said crankshaft.

2. An internal combustion engine comprising a crankshaft, parallel cylinders associated with the crankshaft, a pair of opposed working pistons in each cylinder, a freely movable piston between each pair of working pistons to form a combustion chamber between itself and its'related working pistons alternately, means directly connecting one working piston of each pair to the crankshaft. and means including an inertia member connecting the other working piston of each pair to said crankshaft.

3. An internal combustion engine of the radial type, comprising a two-throw crankshaft, a plurality of cylinders, a pair of opposed working pistons in each cylinder, a freely movable piston between each pair of working pistons to form a combustion chamber between itself and its related working pistons alternately; means directly connecting one working piston of each pair to said two-throw crankshaft and means comprising a U-shaped member connecting the other working piston of each pair to said crankshaft.

IF'lElRNANDO- G. PRIETO. 

